[PATCH] Skip checks in pthread_mutex_destroy when doing elision

When doing elisison the __nusers field is not updated, thus can have an
arbitrary value.

	[BZ #16657]
	* nptl/pthread_mutex_destroy.c (__pthread_mutex_destroy): Skip
	checks when doing elision.
	* nptl/sysdeps/unix/sysv/linux/x86/pthread_mutex_destroy.c: New file.

Index: glibc-2.18/nptl/pthread_mutex_destroy.c
===================================================================
--- glibc-2.18.orig/nptl/pthread_mutex_destroy.c
+++ glibc-2.18/nptl/pthread_mutex_destroy.c
@@ -21,6 +21,9 @@
 
 #include <stap-probe.h>
 
+#ifndef DO_ELISION
+# define DO_ELISION(m) 0
+#endif
 
 int
 __pthread_mutex_destroy (mutex)
@@ -28,7 +31,8 @@ __pthread_mutex_destroy (mutex)
 {
   LIBC_PROBE (mutex_destroy, 1, mutex);
 
-  if ((mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP) == 0
+  if (!DO_ELISION (mutex)
+      && (mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP) == 0
       && mutex->__data.__nusers != 0)
     return EBUSY;
 
Index: glibc-2.18/nptl/sysdeps/unix/sysv/linux/x86/pthread_mutex_destroy.c
===================================================================
--- /dev/null
+++ glibc-2.18/nptl/sysdeps/unix/sysv/linux/x86/pthread_mutex_destroy.c
@@ -0,0 +1,22 @@
+/* Elided version of pthread_mutex_destroy.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <elision-conf.h>
+#include "force-elision.h"
+
+#include "nptl/pthread_mutex_destroy.c"